That happens at the start. You've only just joined, you don't know too many people and you don't know who's gonna jump out of a game as soon as they play a bad shot and who isn't, you don't know who will chuck you out simply for being a hack and who won't.
But keep playing, keep creating multiplayer games, join in the tournaments in the Community organised section, and you'll end up with a group of friends on your list who you can invite whenever you want and they'll nearly always say yes unless they're playing somebody else.
There's good guys out there, you've just got to look for them!